The present invention relates to improvements in fluid power load-clamping systems with automatically variable maximum clamping force control, for optimizing the versatility and speed by which a wide variety of different load types in a warehouse or other storage facility can be properly clamped in a manner automatically adaptive to each load type and configuration.
Load handling clamps typically operate in a storage or shipping facility such as a warehouse or distribution center and must often be capable of handling more than one type, or variety, of load. The clamps in some of these facilities encounter a relatively small number of distinct load types. For example, a load handling clamp being used in a distribution center for a large consumer appliance manufacturer may encounter dishwashers, washing machines, clothes dryers and refrigerators almost exclusively. In other facilities, load handling clamps will encounter a much wider variety of load types. The appliances from the previous example may, for instance, be shipped to a warehouse for a large retail store. The warehouse may also contain computers, furniture, televisions, etc. A clamp may thus encounter cartons having similar outward appearances and dimensions but containing products having differing optimal maximum clamping force requirements due to different load characteristics such as weight, fragility, packaging, etc. A clamp may also not always be required to grip the same number of cartons. For instance a clamp may be utilized to simultaneously move four refrigerator cartons, then to move a single dishwasher carton, and finally a single additional refrigerator carton, presenting different load geometries also having differing optimal maximum clamping force requirements, separate from those arising from the foregoing load characteristics.
Fluid power clamping systems with automatically variable limitations on clamping force usually impose such limitations in a way which limits the speed with which the load-engaging surfaces can be closed into initial contact with the load, thereby limiting the productivity of the load-clamping system. This problem has been reduced in the past by allowing higher maximum fluid closing pressures than optimal maximum fluid pressure during initial closure and then, when the load is about to be contacted by the load-engaging surfaces, decreasing the maximum fluid pressure limit to a limit at or below the optimal limit to clamp the load. However this latter approach, although faster, has not previously been usable compatibly with complex inputs involving both load geometries and load characteristics as described above.